At present, usage of urban roads at night is low, especially during a period from midnight to dawn. If all road lamps on the roads are on all through the night, it would bring about energy waste and inefficiencies, and pollution from power plants would not be ignored either. However, if none or only certain road lamps are on in a certain period of time at night, it would seriously influence normal walking of pedestrians and driving safety of vehicles. Targets of energy-efficiency and emission reduction are also needed to be realized while the safety of pedestrians and vehicles can be ensured.
Some simple road lamp control methods have been disclosed. They, for example, choose to turn off all the lamps on the roads with low traffic flow during a period from midnight to dawn, or to control ON and OFF of all the lamps according to the time of sunset and sunrise or ambient lighting conditions detected by photoelectric devices. These methods can save 20-40% power compared with the method that all lamps are on all through the night, and can prolong service life of road lamps effectively. However, these methods are unable to ensure road safety at night.